Biopsy is a medical diagnostic test used to determine the structure and composition of tissues or cells. In particular, cells or living tissues are sampled from an organ or other body part and are examined under microscope. For example, if an abnormality is found, a biopsy can be performed to determine the exact nature of the suspected abnormality. For example, a physician may perform a biopsy as part of cancer diagnosis in order to determine whether an area of concern is malignant (cancerous) or benign (not cancerous).
Biopsies can be performed on a number of organs, tissues, and body sites. A bone biopsy may be performed if the patient experiences bone pain and/or demonstrates other indicators of bone cancer. A bone marrow biopsy may be performed for individuals with abnormal blood counts. A breast biopsy is performed to confirm if a lesion is benign or malignant. A cervical biopsy is often performed to diagnose cervical diseases such as cervical cancer. Joint biopsy can be used to diagnose gout, pseudogout, bacterial infections, lupus, rheumatoid arthritis or Reiter's disease. Kidney biopsy can be performed to diagnose a long list of disorders including glomerulonrphritis, systemic lupus erythematosus, Wilms' tumour and renal cell cancer, and may be performed if blood is found in the urine, if there is excessive protein in the urine, and in cases of impaired kidney function which causes excessive waste products in the blood. Liver biopsy may help identify liver disorders and diagnose abnormalities as benign or malignant. Lymph node biopsy can be performed to look for diseases such as chronic lymphatic leukemia, Hodgkin's disease, infectious mononucleosis, and rheumatoid arthritis, and can be used to determine the stage of cancer by checking whether the cancer has spread from the primary location into the lymphatic system. Lung biopsy is performed to confirm lung diseases such as cancer and to diagnose abnormalities. Pleural biopsy is sampling of the pleura (the sac that covers the lungs) and may be performed to differentiate between malignant and non-malignant disease and to diagnose various diseases of the pleura (e.g. viral, fungal, parasitic, or collagen vascular disease). Prostate biopsy can be used to diagnose prostate cancer or to determine the cause of prostate enlargement or elevated serum prostate markers (e.g. PSA—prostate specific antigen). Small intestine biopsy is often performed to determine what may be causing diarrhea or poor absorption in the intestine. Skin biopsy is used to test for malignant cancer and to diagnose various skin infections. Synovial biopsy is used to sample synovial tissue from the surface of a joint. Thyroid and parathyroid biopsy maybe used to diagnose people with thyroid enlargement or nodules, breathing and swallowing difficulties, vocal chord paralysis and other problems such as unexplainable weight loss. Thyroid biopsy may also be used to diagnose Hashimoto's disease, hyperthyroidism, and nontoxic nodular goiter. A biopsy may also be performed to sample the following organs to test for cancer and other diseases: adrenal gland, biliary tract, bladder, carpal tunnel, colon, endometrium, gingiva (gums), heart, muscle, nerve, salivary gland, small bowel, mouth, nasal mucosa, rectum, testicle, throat, and tongue.
The type of biopsy procedure used to obtain a required tissue sample depends on a variety of factors including: the tissue or body part to be sampled, the location, size, shape and other characteristics of the abnormality, the number of abnormalities, and patient preference. Aspiration or FNA (fine needle aspiration) biopsy is a percutaneous biopsy performed using fine gauge needle (22 or 25 gauge) attached to a syringe. Cone biopsy removes a generally cylindrical or cone shaped piece of tissue using either the LEEP method (loop electrosurgical excision procedure) wherein tissue is removed using an electrically heated wire, or a method using a surgical scalpel or laser to remove the tissue. Core needle biopsy is a percutaneous procedure performed by inserting a small hollow needle through the skin and into the abnormality such that a sample or core is removed as the needle is advanced through the cell layers. A suction or vacuum assisted core biopsy is generally a core biopsy using vacuum assistance to pull the sample from the collection site. Endoscopic biopsy is a biopsy performed through an endoscope (a fiber optic cable for viewing inside the body), wherein samples may be removed using forceps attached to a cable that runs inside the endoscope. A punch biopsy uses a sharp, hollow instrument (like a cookie cutter) to remove a cylindrical piece of skin, for example, from a mole. A surface biopsy involves sampling or scraping off superficial levels of skin and is often performed by dermatologists to remove a small piece of skin to test for carcinoma. Surgical/excisional biopsy is generally performed as an open procedure and can be either excisional (removal of an entire lesion) or incisional (removal of a piece of a lesion).
Fine needle biopsies, unlike surgical biopsies, cannot remove the entire lesion and misdiagnosis can occur. Core needle biopsy removes more tissue than fine needle biopsy and, thus, may provide a more accurate analysis and diagnosis. However, this procedure is not accurate in patients with very small or hard lumps. While surgical biopsies remove more tissues and, thus, less prone to misdiagnosis, these procedures are significantly more expensive than needle biopsies, require more time for recuperation, require sutures, can leave a disfiguring scar, require anesthesia, carry a small risk of mortality, and can result in bleeding, infection and wound healing problems.
Brush biopsy or cytology is a type of sampling procedure wherein a brush having stiff bristles is inserted to the site and sample is collected as the bristles of the brush scrape or rub against the collection site. This method has been reported to obtain a complete transepithelial biopsy specimen from each of the three layers of the lesion (the basal, intermediate, and superficial layers). Such procedures find particular use in connection with many epithelial cancers and can be used to take rectal, cervical, and bladder samples. However, with such methods, only tiny pieces of tissue are obtained, and the brush must be removed from the site, the sample collected from the brush, and the brush reinserted to the site multiple times to collect an adequate sample for analysis.